1. Field of the Invention
The present invention relates generally to energy efficient Ethernet (EEE) and, more particularly, to a system and method for loop timing update of energy efficient physical layer devices using subset communication techniques.
2. Introduction
Energy costs continue to escalate in a trend that has accelerated in recent years. Such being the case, various industries have become increasingly sensitive to the impact of those rising costs. One area that has drawn increasing scrutiny is the IT infrastructure. Many companies are now looking at their IT systems' power usage to determine whether the energy costs can be reduced. For this reason, an industry focus on energy efficient networks has arisen to address the rising costs of IT equipment usage as a whole (i.e., PCs, displays, printers, servers, network equipment, etc.).
Energy-savings requirements are rapidly being mandated for a variety of wireline and wireless applications. Here, energy-savings initiatives have identified the need for energy efficiency of physical layer devices (PHYs). In one example, energy efficiency of PHYs can be produced by enabling the PHYs to enter into a low-power mode during which there is no data, video and/or audio data for transmission.
In designing an energy efficient solution, one of the considerations is the utilization of the network link. For example, many network links are typically in an idle state between sporadic bursts of data, while in other network links, there can be regular or intermittent low-bandwidth traffic, with bursts of high-bandwidth traffic. Conventionally, an EEE control policy can analyze the link utilization to determine whether to adapt the link, link rate, and layers above the link to an optimal solution based on various energy costs and impact on traffic.
In effecting a proper EEE control policy, one of the significant factors is the ability to which an energy-efficient PHY can wake up quickly and reliably when the higher layers of the network detect and request traffic exchange. This transition time can greatly impact the aggressiveness of the EEE control policy in its attempt to realize energy savings within the PHY. Moreover, this transition time can impact the amount of buffering that may need to be allocated in ensuring that traffic is not lost. What is needed therefore is a mechanism that improves the ability of the PHY to wake up quickly and reliably from a low-power mode.